Changelog: Photos Page

I've created a Photos page to show off the photography-tagged posts in a gallery format.

It didn't take much coding work to build, just adding on a "thumb" mode to the image builtin. The majority of the work was achievable with pre-existing template builtins:

<main>
  <section>
  <h1>Photos</h1>
  <div class="gallery">
    {setlist(posts, contains(item.md.tags, photography))/}
    {foreach(posts, post)/}
      {if(post.md.thumbnail)/}
      <a href="{pageurl(post.md.slug)}">
        {img(post.md.thumbnail, thumb)}
      </a>
      {/if}
    {/foreach}
    {/setlist}
  </div>
  </section>
</main>